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Muva nje, kusungulwe iplathifomu ye-antimicrobial engenamakhemikhali esekelwe ku-nanotechnology esebenzisa ama-nanostructures amanzi okwenziwa (EWNS) yenziwe. I-EWNS inokushaja okuphezulu kwendawo futhi inothe ngezinhlobo ze-oxygen esebenzayo (i-ROS) engasebenzisana futhi yenze inani lezilwanyana ezincane zisebenze, okuhlanganisa amagciwane atholakala ekudleni. Lapha kuboniswa ukuthi izakhiwo zabo ngesikhathi sokuhlanganiswa zingacutshungulwa kahle futhi zenziwe ngcono ukuze kuthuthukiswe amandla abo e-antibacterial. Inkundla yelabhorethri ye-EWNS yakhelwe ukulungisa kahle izakhiwo ze-EWNS ngokushintsha amapharamitha wokuhlanganisa. Ukuhlukaniswa kwezakhiwo ze-EWNS (inkokhelo, usayizi, nokuqukethwe kwe-ROS) kwenziwa kusetshenziswa izindlela zesimanje zokuhlaziya. Ngaphezu kwalokho, ama-microorganisms okudla afana ne-Escherichia coli, i-Salmonella enterica, i-Listeria innocua, i-Mycobacterium para fortitum, ne-Saccharomyces cerevisiae yajova ebusweni bukatamatisi wamagilebhisi we-organic ukuze kuhlolwe amandla abo okungasebenzi kwe-microbial. Imiphumela evezwe lapha ibonisa ukuthi izici ze-EWNS zingacushwa kahle ngesikhathi sokuhlanganiswa, okuholela ekwenyukeni okukhulu kokungasebenzi kahle kokusebenza. Ikakhulukazi, ukushaja okungaphezulu kwanda ngesilinganiso sezine, futhi okuqukethwe kwe-ROS kwanda. Izinga lokususwa kwe-microbial lalincike ku-microbially futhi lalisuka ku-1.0 ukuya ku-3.8 log ngemva kwemizuzu engu-45 yokuchayeka kudosi ye-aerosol engu-40,000 #/cm3 EWNS.
Ukungcoliswa kwamagciwane kuyimbangela eyinhloko yokugula okubangelwa ukudla okubangelwa ukungenwa amagciwane noma ubuthi bawo. Izifo ezibangelwa ukudla zibangela izifo ezingaba yizigidi ezingu-76, ukulaliswa ezibhedlela ezingu-325,000, nokufa kwabangu-5 000 unyaka ngamunye e-United States kuphela1. Ngaphezu kwalokho, uMnyango Wezolimo Wase-United States (i-USDA) ulinganisela ukuthi ukusetshenziswa okwengeziwe komkhiqizo omusha kuyimbangela yamaphesenti angu-48 azo zonke izifo ezitholakala ngokudla ezibikwe e-United States2. Izindleko zokugula nokufa okubangelwa amagciwane atholakala ekudleni e-United States ziphezulu kakhulu, zilinganiselwa yiCenters for Disease Control and Prevention (CDC) ezingaphezu kwezigidigidi ezingama-US $15.6 ngonyaka3.
Njengamanje, ukungenelela kwamakhemikhali4, ama-radiation5 kanye ne-thermal6 okulwa namagciwane ukuze kuqinisekiswe ukuphepha kokudla kwenziwa ikakhulukazi ezindaweni zokulawula ezibucayi (CCPs) ochungechungeni lokukhiqiza (imvamisa ngemva kokuvuna kanye/noma phakathi nokupakisha) kunokuba kuqhutshekwe kusetshenziswa ngendlela yokuthi umkhiqizo omusha ubhekane nokungcoliswa 7. Ukungenelela kwama-antimicrobial kuyadingeka ukuze kulawuleke kangcono ukudla okonakalayo futhi kulawuleke kangcono ukudla okonakalayo. ipulazi kuya etafuleni ukuqhubeka. Umthelela omncane kanye nezindleko.
Inkundla yemithi elwa namagciwane esekelwe ku-nanotechnology isanda kwakhiwa ukuze ingasebenzi amagciwane endaweni nasemoyeni kusetshenziswa ama-nanostructures amanzi okwenziwa (EWNS). Ukuze kuhlanganiswe i-EVNS, izinqubo ezimbili ezihambisanayo zasetshenziswa: i-electrospray kanye ne-ionization yamanzi (Fig. 1a). Ngaphambilini i-EWNS ikhonjiswe ukuthi inesethi ehlukile yezakhiwo zemvelo nezamabhayoloji8,9,10. I-EWNS inesilinganiso sama-electron angu-10 isakhiwo ngasinye kanye nosayizi we-nanometer ophakathi kuka-25 nm (Fig. 1b,c)8,9,10. Ukwengeza, i-electron spin resonance (ESR) ibonise ukuthi i-EWNS iqukethe inani elikhulu lezinhlobo ze-oxygen esebenzayo (ROS), ikakhulukazi i-hydroxyl (OH•) ne-superoxide (O2-) radicals (Fig. 1c) 8. I-EWNS yahlala emoyeni isikhathi eside futhi yayikwazi ukungqubuzana namagciwane amisiwe emoyeni futhi abe khona ezindaweni ezingaphezulu, alethe inkokhelo yawo ye-ROS futhi abangele ukungasebenzi kwe-microbial (Fig. 1d). Lezi zifundo zangaphambili ziphinde zabonisa ukuthi i-EWNS ingasebenzisana futhi yenze amagciwane ahlukahlukene e-gram-negative kanye negram-positive abalulekile empilweni yomphakathi, okuhlanganisa i-mycobacteria, endaweni kanye nasemoyeni8,9. I-microscopy ye-electron yokudlulisela ibonise ukuthi ukungasebenzi kwakubangelwa ukuphazamiseka kwe-membrane yeseli. Ukwengeza, izifundo zokuhogela ngokunamandla zibonise ukuthi imithamo ephezulu ye-EWNS ayidali monakalo wamaphaphu noma ukuvuvukala8.
(a) I-Electrospray yenzeka lapho kusetshenziswa amandla kagesi aphezulu phakathi kwe-capillary equkethe uketshezi kanye ne-counter electrode. (b) Ukusetshenziswa kwamandla kagesi aphezulu kubangela izenzakalo ezimbili ezihlukene: (i) ukufafazwa kwamanzi ngogesi kanye (ii) nokukhiqizwa kwezinhlobo zomoya-mpilo osebenzayo (ama-ion) avaleleke ku-EWNS. (c) Isakhiwo esiyingqayizivele se-EWNS. (d) Ama-EWNS ahamba kakhulu ngenxa yemvelo yawo ye-nanoscale futhi angaxhumana namagciwane ahamba emoyeni.
Ikhono lenkundla ye-EWNS ye-antimicrobial yokuvala ama-microorganisms atholakala ekudleni endaweni yokudla okusha nawo abonisiwe muva nje. Kuphinde kwaboniswa ukuthi i-EWNS surface charge ingasetshenziswa ngokuhambisana nenkundla kagesi ukuze kuhanjiswe okuhlosiwe. Okubaluleke nakakhulu, umphumela othembisayo wokuqala cishe wokwehliswa kwelogi elingu-1.4 kumsebenzi katamatisi wemvelo ngokumelene nama-microorganisms ahlukahlukene okudla afana ne-E. coli ne-Listeria yabonwa phakathi nemizuzu engu-90 yokuchayeka ku-EWNS ekuhlanganiseni okucishe kube ngu-50,000#/cm311. Ngaphezu kwalokho, ukuhlolwa kokuhlolwa kwe-organoleptic kokuqala akuzange kubonise umphumela we-organoleptic uma kuqhathaniswa notamatisi wokulawula. Nakuba le miphumela yokuqala yokungasebenzi ithembisa ukuphepha kokudla ngisho nangemithamo ephansi ye-EWNS engu-50,000#/cc. bheka, kusobala ukuthi amandla aphezulu okungasebenzi angaba yinzuzo eyengeziwe ekunciphiseni ingozi yokutheleleka kanye nokonakala.
Lapha, sizogxila ocwaningweni lwethu ekuthuthukisweni kwenkundla yesizukulwane se-EWNS ukuze sishune kahle imingcele yokuhlanganisa futhi sithuthukise izici ze-physicochemical ze-EWNS ukuze kuthuthukiswe amandla ayo okulwa namagciwane. Ikakhulukazi, ukwenza kahle kugxile ekwandiseni ukushaja kwazo okungaphezulu (ukuthuthukisa ukulethwa okuhlosiwe) nokuqukethwe kwe-ROS (ukuthuthukisa ukusebenza kahle kokungasebenzisi). Ukucaciswa kwezakhiwo ze-physico-chemical ezithuthukisiwe (usayizi, inkokhiso kanye nokuqukethwe kwe-ROS) kusetshenziswa izindlela zesimanje zokuhlaziya nokusebenzisa ama-microorganisms okudla avamile afana ne-E. coli, S. enterica, L. innocua, S. cerevisiae kanye ne-M. parafortuitum.
I-EVNS yahlanganiswa nge-electrospraying kanyekanye kanye ne-ionization yamanzi ahlanzekile aphezulu (18 MΩ cm–1). I-atomizer kagesi 12 ijwayele ukusetshenziselwa ukwenza i-atomize uketshezi kanye ne-polymer yokwenziwa kanye nezinhlayiya ze-ceramic 13 kanye namafayibha angu-14 osayizi olawulwayo.
Njengoba kuchaziwe ekushicilelweni kwangaphambilini 8, 9, 10, 11, ekuhlolweni okujwayelekile, i-voltage ephezulu isetshenziswa phakathi kwe-capillary yensimbi ne-grounded counter electrode. Phakathi nale nqubo, kwenzeka izinto ezimbili ezihlukene: 1) i-electrospray kanye ne-2) i-ionization yamanzi. Inkambu eqinile kagesi phakathi kwama-electrode amabili ibangela ukuthi amashaji angemahle akheke phezu kwamanzi ajiyile, okuholela ekwakhekeni kwama-Taylor cones. Ngenxa yalokho, kwakheka amaconsi amanzi ashajwe kakhulu, aqhubeka ehlukana abe yizinhlayiya ezincane, ngokusho kwe-Rayleigh theory16. Ngesikhathi esifanayo, insimu kagesi enamandla ibangela ukuthi amanye ama-molecule amanzi ahlukanise futhi akhiphe ama-electron (ionization), ngaleyo ndlela akhiqize inani elikhulu lezinhlobo ze-oxygen esebenzayo (ROS)17. Amaphakethe e-ROS18 akhiqizwe kanyekanye afakwe ku-EWNS (Fig. 1c).
Emkhiwaneni. I-2a ikhombisa uhlelo lokuzala lwe-EWNS olwakhiwe futhi lwasetshenziswa ekuhlanganiseni kwe-EWNS kulolu cwaningo. Amanzi ahlanzekile agcinwe ebhodleleni elivaliwe ayephakelwa ngeshubhu le-Teflon (ububanzi obuyi-2 mm bangaphakathi) enalithi yensimbi engenasici engu-30G (i-metal capillary). Njengoba kuboniswe kuMfanekiso 2b, ukugeleza kwamanzi kulawulwa ukucindezela komoya ngaphakathi kwebhodlela. Inaliti ixhunywe kukhonsoli ye-Teflon engalungiswa ngesandla ibe ibanga elithile ukusuka ku-electrode yokubala. I-counter electrode iyidiski ye-aluminium epholishiwe enembobo phakathi ukuze kuthathwe amasampula. Ngezansi kwekhawunta ye-electrode kunefaneli yesampula ye-aluminium, exhunywe kukho konke ukusetha kokuhlola ngembobo yesampula (Fig. 2b). Zonke izingxenye zesampula zisekelwe ngogesi ukuze kugwenywe ukunqwabelana kwezindleko okungase kwehlise isithunzi sokusampula kwezinhlayiyana.
(a) Uhlelo Lokukhiqiza Nanostructure Yamanzi Enjiniyela (EWNS). (b) Ingxenye ephambanayo yesampula yesampula kanye neyunithi ye-electrospray ebonisa amapharamitha abaluleke kakhulu. (c) Ukusethwa kokuhlola kokungasebenzi kwamagciwane.
Isistimu yokukhiqiza ye-EWNS echazwe ngenhla iyakwazi ukushintsha amapharamitha angukhiye wokusebenza ukuze kube lula ukuhlela kahle izakhiwo ze-EWNS. Lungisa i-voltage esetshenzisiwe (V), ibanga phakathi kwenaliti kanye ne-electrode yokubala (L), nokugeleza kwamanzi (φ) nge-capillary ukuze ulungise kahle izici ze-EWNS. Izimpawu [V (kV), L (cm)] zisetshenziselwa ukuchaza inhlanganisela ehlukene. Lungisa ukugeleza kwamanzi ukuze uthole ikhoni ka-Taylor ezinzile yesethi ethile [V, L]. Ngezinjongo zalolu cwaningo, indawo yokuvula i-electrode ekhawuntayo (D) isethwe kumayintshi angu-0.5 (1.29 cm).
Ngenxa yejometri elinganiselwe kanye ne-asymmetry, amandla enkambu kagesi awakwazi ukubalwa kusukela kuzimiso zokuqala. Esikhundleni salokho, isofthiwe ye-QuickField™ (Svendborg, Denmark)19 yasetshenziswa ukubala indawo kagesi. Inkambu kagesi ayifani, ngakho-ke inani lenkambu kagesi ekugcineni kwe-capillary lisetshenziswe njengenani elibhekisela ekucushweni okuhlukahlukene.
Phakathi nocwaningo, izinhlanganisela eziningana zamandla kagesi kanye nebanga phakathi kwenaliti kanye ne-electrode yokubala zihlolwe ngokokwakheka kwe-Taylor cone, ukuqina kwe-Taylor cone, ukuzinza kokukhiqiza kwe-EWNS, kanye nokuzala kabusha. Inhlanganisela ehlukahlukene ikhonjiswe kokuthi Ithebula Le-Supplementary S1.
Ukukhishwa kwesistimu yokukhiqiza ye-EWNS kwakuxhunywe ngokuqondile ku-Scanning Mobility Particle Sizer (SMPS, imodeli 3936, TSI, Shoreview, Minnesota) ukuze kulinganiswe ukugxiliswa kwenombolo yezinhlayiyana futhi kwasetshenziswa ne-Faraday aerosol electrometer (TSI, imodeli 3068B, Shoreview, USA). MN) ukukala ukugeleza kwe-aerosol, njengoba kuchazwe ekushicilelweni kwethu kwangaphambilini9. Kokubili i-SMPS ne-electrometer ye-aerosol okuthathwe ngesilinganiso sokugeleza esingu-0.5 L/min (isamba sokugeleza kwesampula 1 L/min). Ukugxila kwezinhlayiya kanye nokuguquguquka kwe-aerosol kukalwa ngamasekhondi ayi-120. Phinda ukulinganisa izikhathi ezingu-30. Isamba sokushajwa kwe-aerosol sibalwa kusukela ezilinganisweni zamanje, futhi inkokhiso emaphakathi ye-EWNS ilinganiselwa kusuka enanini eliphelele lezinhlayiya ze-EWNS ezisampula. Isilinganiso sezindleko ze-EWNS singabalwa kusetshenziswa i-Equation (1):
lapho i-Iel ingumthamo wamanje okaliwe, i-NSMPS ukugxiliswa kwenombolo kukalwa nge-SMPS, futhi u-φEl izinga lokugeleza ku-electrometer.
Ngenxa yokuthi umswakama ohlobene (RH) uthinta ukushajwa kwendawo, izinga lokushisa kanye (RH) zigcinwe zingashintshile ku-21°C no-45%, ngokulandelana, ngesikhathi sokuhlolwa.
I-Atomic force microscopy (AFM), i-Asylum MFP-3D (Asylum Research, Santa Barbara, CA) kanye ne-AC260T probe (Olympus, Tokyo, Japan) zisetshenziswe ukukala usayizi nempilo yonke ye-EWNS. Izinga lokuskena kwe-AFM ngu-1 Hz futhi indawo yokuskena ingu-5 µm×5 µm enemigqa yokuskena engu-256. Zonke izithombe zibe ngaphansi kokuqondisa kwesithombe se-oda lokuqala kusetshenziswa isofthiwe ye-Asylum (imaski enobubanzi obungu-100 nm kanye nomkhawulo ongu-100 pm).
Susa ifaneli yesampula bese ubeka i-mica surface ebangeni elingu-2.0 cm ukusuka ku-electrode yekhawunta isikhathi esimaphakathi samasekhondi angu-120 ukuze ugweme ukuhlangana kwezinhlayiya nokwakheka kwamaconsi angajwayelekile endaweni ye-mica. I-EWNS isetshenziswe ngokuqondile ezindaweni ezisanda kusikwa ze-mica (Ted Pella, Redding, CA). Ngokushesha ngemva kokufafaza, i-mica surface yabonwa ngeso lengqondo kusetshenziswa i-AFM. I-engeli yokuxhumana engaphezulu ye-mica engashintshiwe esanda kusikwa isondele ku-0°, ngakho-ke i-EWNS isakaza phezu kwendawo ye-mica ngendlela ebunjwayo20. Ububanzi (a) nobude (h) bamaconsi asakazekayo kukalwa ngokuqondile ku-AFM topography futhi kwasetshenziswa ukubala ivolumu yokusabalalisa okune-domed EWNS kusetshenziswa indlela yethu egunyazwe ngaphambilini8. Ngokucabangela ukuthi i-EVNS esemkhunjini inevolumu efanayo, ububanzi obulinganayo bungabalwa ukusuka kusibalo (2):
Ngokuhambisana nendlela yethu eyakhiwe ngaphambilini, i-electron spin resonance (ESR) spin trap yasetshenziswa ukuthola ukuba khona kwama-radical intermediate esikhashana ku-EWNS. Ama-aerosols adluliswa ngesisombululo esiqukethe i-235 mM DEPMPO (5-(diethoxyphosphoryl) -5-methyl-1-pyrroline-N-oxide) (Oxis International Inc., Portland, Oregon). Zonke izilinganiso ze-EPR zenziwe kusetshenziswa i-spectrometer ye-Bruker EMX (i-Bruker Instruments Inc. Billerica, MA, USA) kanye nezinhlaka zamaseli ayisicaba. Isofthiwe ye-Acquisit (Bruker Instruments Inc. Billerica, MA, USA) isetshenziselwe ukuqoqa nokuhlaziya idatha. Ukulinganisa kwe-ROS kwenziwa kuphela kusethi yezimo zokusebenza [-6.5 kV, 4.0 cm]. Ukugxiliswa kwe-EWNS kukalwe kusetshenziswa i-SMPS ngemva kokucabangela ukulahlekelwa kwe-EWNS ku- impactor.
Amazinga e-ozone aqashwe kusetshenziswa i-205 Dual Beam Ozone Monitor™ (2B Technologies, Boulder, Co)8,9,10.
Kuzo zonke izici ze-EWNS, inani lokulinganisa liyincazelo yezilinganiso, futhi iphutha lokulinganisa liwukuchezuka okujwayelekile. Ukuhlolwa kuka-t kwenziwe ukuze kuqhathaniswe inani lesibaluli esithuthukisiwe se-EWNS nevelu elihambisanayo le-EWNS eyisisekelo.
Umfanekiso 2c ukhombisa i-Electrostatic Precipitation Pass Through System (EPES) eyakhiwe ngaphambilini futhi enezimpawu ezingasetshenziswa ukukhomba i-EWNS11 ezindaweni. I-EPES isebenzisa ishaja ye-EWNS ihlanganiswe nenkambu kagesi eqinile ukuze “ikhombe” ngokuqondile endaweni eqondiwe. Imininingwane yohlelo lwe-EPES yethulwa ekushicilelweni kwakamuva nguPyrgiotakis et al.11. Ngakho, i-EPES iqukethe igumbi le-PVC eliphrintiwe le-3D elineziphetho ezicijile eziqukethe insimbi engagqwali ehambisanayo engu-304 (insimbi engagqwali engu-304, epholishelwe isibuko) amapuleti ensimbi phakathi nendawo eyi-15.24 cm ukuhlukana. Amabhodi ayexhunywe kumthombo wamandla kagesi aphezulu wangaphandle (Bertran 205B-10R, Spellman, Hauppauge, NY), ibhodi elingezansi lalihlala lihle futhi ibhodi eliphezulu lalihlala liphansi (lintanta). Izindonga zegumbi zimbozwe nge-aluminium foil, esekelwe ngogesi ukuvimbela ukulahleka kwezinhlayiyana. Igumbi linomnyango olayishiwe ovaliwe ongaphambili ovumela izindawo zokuhlola ukuthi zibekwe kuma-rack epulasitiki, azisuse epuleti lensimbi elingaphansi ukugwema ukuphazamiseka kwamandla kagesi aphezulu.
Ukusebenza kahle kokufakwa kwe-EWNS ku-EPES kubalwe ngokomthetho olandelwayo owenziwe ngaphambilini ochazwe ku-Supplementary Figure S111.
Njengegumbi lokulawula, ukugeleza kwesibili ngegumbi le-cylindrical kuxhunywe ochungechungeni nohlelo lwe-EPES kusetshenziswa isihlungi se-HEPA esiphakathi ukuze kukhishwe i-EWNS. Njengoba kuboniswe emkhiwaneni. 2c, i-aerosol ye-EWNS yampontshwa emagumbini amabili axhunywe ochungechungeni. Isihlungi esiphakathi kwegumbi lokulawula ne-EPES sisusa noma iyiphi i-EWNS esele eholela ezingeni lokushisa elifanayo (T), umswakama ohlobene (RH) namazinga we-ozone.
Amagciwane abalulekile atholakala ekudleni atholwe ukuthi angcolise umkhiqizo omusha njenge-Escherichia coli (ATCC #27325), inkomba ye-fecal, i-Salmonella enterica (ATCC #53647), i-pathogen etholakala ekudleni, i-Listeria innocua (ATCC #33090), enye indlela ye-pathogenic Listeria monocy. , i-Saccharomyces cerevisiae (ATCC #4098) njengenye indlela ye-spoilage yeast, kanye ne-Mycobacterium parafortuitous (ATCC #19686) njengebhaktheriya eliphilayo elimelana kakhudlwana zathengwa kwa-ATCC (Manassas, Virginia).
Thenga ngokungahleliwe amabhokisi otamatisi wamagilebhisi wemvelo emakethe yangakini bese uwafaka efrijini ku-4°C uze usetshenziswe (kufika ezinsukwini ezi-3). Khetha utamatisi ukuze uzame usayizi owodwa, cishe u-1/2 intshi ububanzi.
Izinqubo zokufukamela, ukujova, ukuchayeka nokubalwa kwekoloni ziye zachazwa kabanzi ezincwadini zethu zangaphambilini futhi zachazwa ngokuningiliziwe ku-Supplementary Data 11. Ukusebenza kwe-EWNS kwahlolwa ngokudalula utamatisi ogonyelwe ku-40,000 #/cm3 imizuzu engu-45. Kafushane, ngesikhathi t = 0 min, utamatisi amathathu asetshenziselwa ukuhlola ama-microorganisms asaphila. Utamatisi amathathu afakwe ku-EPES futhi avezwa ku-EWNS ku-40,000 #/cc (EWNS utamatisi oveziwe) kanti amanye amathathu afakwe ekamelweni lokulawula (utamatisi wokulawula). Awekho amaqembu katamatisi afakwe ngaphansi kokucubungula okwengeziwe. Utamatisi nezilawuli eziveziwe ze-EWNS zikhishwe ngemva kwemizuzu engu-45 ukuhlola umphumela we-EWNS.
Ukuhlolwa ngakunye kwenziwa ngokuphindwe kathathu. Ukuhlaziywa kwedatha kwenziwa ngokuvumelana nephrothokholi echazwe ku-Supplementary Data.
I-E. coli, i-Enterobacter, ne-L. amasampula ebhaktheriya e-innocua adalulwe ku-EWNS (45 min, EWNS i-aerosol concentration 40,000 #/cm3) futhi engaveziwe aye afakwa ama-pellets ukuze kuhlolwe izindlela zokungasebenzi. Imvula yalungiswa amahora angu-2 ekamelweni lokushisa ku-0.1 M isixazululo se-sodium cacodylate (pH 7.4) ne-fixative ye-2.5% glutaraldehyde, 1.25% paraformaldehyde kanye ne-0.03% ye-picric acid. Ngemva kokuwashwa, ahlanganiswe ne-1% osmium tetroxide (OsO4)/1.5% potassium ferrocyanide (KFeCN6) amahora angu-2, ahlanjwe izikhathi ezingu-3 ngamanzi futhi afakwe ku-1% uranyl acetate ihora elingu-1, bese ewashwa kabili ngamanzi. Ukuphelelwa amanzi emzimbeni okwalandela imizuzu eyi-10 ngayinye ka-50%, 70%, 90%, 100% utshwala. Amasampula abe esefakwa ku-propylene oxide ihora elingu-1 futhi afakwe ingxube engu-1:1 ye-propylene oxide ne-TAAP Epon (Marivac Canada Inc. St. Laurent, CA). Amasampuli ashumekwe ku-TAAB Epon futhi enziwe i-polymerized ku-60°C amahora angu-48. I-resin ye-granular ephulukisiwe yasikwa futhi yabonwa yi-TEM kusetshenziswa i-JEOL 1200EX (JEOL, Tokyo, Japan), isibonakhulu se-electron yokudlulisa efakwe ikhamera ye-AMT 2k CCD (Advanced Microscopy Techniques, Corp., Woburn, MA, USA).
Zonke izivivinyo zenziwa ngokuphindwe kathathu. Ephuzwini ngalinye lesikhathi, ukugezwa kwamagciwane kwakuhlanganiswe kathathu, okuholele enanini lamaphoyinti edatha ayisishiyagalolunye ngephuzu ngalinye, isilinganiso sawo esisetshenziswe njengokugxiliswa kwebhaktheriya kuleyo nto ephilayo. Ukuchezuka okujwayelekile kusetshenziswe njengephutha lokulinganisa. Wonke amaphuzu abalwa.
I-logarithm yokuncipha kokuhlangana kwamagciwane uma kuqhathaniswa no-t = 0 min ibalwe kusetshenziswa ifomula elandelayo:
lapho i-C0 iwukuhlangana kwamagciwane kusampula yokulawula ngesikhathi 0 (okungukuthi ngemva kokuba ubuso bomile kodwa ngaphambi kokubekwa egunjini) kanye ne-Cn ukugcwala kwamagciwane endaweni ngemva kwemizuzu engu-n yokuchayeka.
Ukulandisa ngokucekelwa phansi kwemvelo kwamabhaktheriya ngesikhathi sokuchayeka kwamaminithi angu-45, Ukuncishiswa Kwelogi nakho kubalwe uma kuqhathaniswa nokulawula emaminithini angu-45 ngendlela elandelayo:
Lapho i-Cn iwukuhlangana kwamabhaktheriya kusampula yokulawula ngesikhathi n kanye ne-Cn-Control ukugxila kokulawula amagciwane ngesikhathi n. Idatha yethulwa njengokwehliswa kwelogi uma kuqhathaniswa nokulawula (akukho ukuchayeka kwe-EWNS).
Phakathi nocwaningo, izinhlanganisela eziningana zamandla kagesi kanye nebanga phakathi kwenaliti kanye ne-electrode yokubala zihlolwe ngokokwakheka kwe-Taylor cone, ukuqina kwe-Taylor cone, ukuzinza kokukhiqiza kwe-EWNS, kanye nokuzala kabusha. Inhlanganisela ehlukahlukene ikhonjiswe kokuthi Ithebula Le-Supplementary S1. Amacala amabili akhethelwe ucwaningo oluphelele olubonisa izakhiwo ezinzile nezikwazi ukukhiqiza kabusha (i-Taylor cone, ukukhiqizwa kwe-EWNS, nokuzinza ngokuhamba kwesikhathi). Emkhiwaneni. 3 ikhombisa imiphumela yenkokhiso, usayizi nokuqukethwe kwe-ROS ngamacala amabili. Imiphumela iphinde ifingqiwe kuThebula 1. Ngokwereferensi, uMdwebo 3 kanye neThebula 1 zihlanganisa izici ze-EWNS8, 9, 10, 11 (eyisisekelo-EWNS) eyahlanganiswa ngaphambilini engathuthukisiwe. Izibalo zokubaluleka kwezibalo zisebenzisa i-t-test enemisila emibili zishicilelwa kabusha ku-Supplementary Table S2. Ukwengeza, idatha eyengeziwe ihlanganisa izifundo ngomphumela we-counter electrode isampula yembobo ububanzi (D) kanye nebanga phakathi kwe-electrode yaphansi kanye nesihloko senaliti (L) (Izibalo Ezingeziwe S2 kanye ne-S3).
(a–c) Ukusabalalisa usayizi we-AFM. (d – f) Isici sokushaja okungaphezulu. (g) Ukucaciswa kwe-ROS ne-ESR.
Kubalulekile futhi ukuqaphela ukuthi kuzo zonke lezi zimo ezingenhla, ama-ionization currents alinganisiwe ayekububanzi obungu-2-6 µA, futhi ama-voltage ayeku- -3.8 kuya ku- -6.5 kV, okuholele ekusetshenzisweni kwamandla kule EWNS yesikhumulo esisodwa esingaphansi kuka-50 mW. . imojula yokukhiqiza. Nakuba i-EWNS yahlanganiswa ngaphansi kwengcindezi ephezulu, amazinga e-ozone ayephansi kakhulu, engakaze adlule ku-60 ppb.
Umfanekiso Owengeziwe we-S4 ubonisa izinkambu zikagesi ezilingisiwe zezimo [-6.5 kV, 4.0 cm] kanye no-[-3.8 kV, 0.5 cm], ngokulandelana. Izinkambu ngokwezimo [-6.5 kV, 4.0 cm] kanye [-3.8 kV, 0.5 cm] zibalwa njengo-2 × 105 V/m no-4.7 × 105 V/m, ngokulandelana. Lokhu kufanele kulindelwe, njengoba isilinganiso se-voltage nebanga siphezulu kakhulu esimweni sesibili.
Emkhiwaneni. 3a,b ikhombisa ububanzi be-EWNS obukalwa nge-AFM8. Isilinganiso samadiamitha e-EWNS sezimo ze-[-6.5 kV, 4.0 cm] kanye nezingu-[-3.8 kV, 0.5 cm] abalwe njengo-27 nm no-19 nm, ngokulandelana. Ukuchezuka okujwayelekile kwejiyomethri kokusatshalaliswa kwamakesi [-6.5 kV, 4.0 cm] kanye no-[-3.8 kV, 0.5 cm] kungu-1.41 no-1.45, ngokulandelana, okubonisa ukusabalalisa kosayizi omncane. Kokubili usayizi omaphakathi kanye nokuchezuka okujwayelekile kwejiyomethri kusondele kakhulu kusisekelo-EWNS, okungu-25 nm no-1.41, ngokulandelanayo. Emkhiwaneni. I-3c ibonisa ukusatshalaliswa kosayizi we-EWNS eyisisekelo elinganiswa kusetshenziswa indlela efanayo ngaphansi kwezimo ezifanayo.
Emkhiwaneni. 3d, e ikhombisa imiphumela yokushaja abalingisi. Idatha izilinganiso ezimaphakathi zezilinganiso ezingama-30 ngesikhathi esisodwa zokugxilisa ingqondo (#/cm3) kanye nezamanje (I). Ukuhlaziywa kukhombisa ukuthi inkokhiso emaphakathi ku-EWNS ingu-22 ± 6 e- kanye no-44 ± 6 e- ku-[-6.5 kV, 4.0 cm] kanye no-[-3.8 kV, 0.5 cm], ngokulandelana. Uma kuqhathaniswa ne-Baseline-EWNS (10 ± 2 e-), ukushajwa kwawo okungaphezulu kuphezulu kakhulu, okuphindwe kabili kunesimo se-scenario [-6.5 kV, 4.0 cm] kanye nokuphindwe kane kune [-3 .8 kV, 0.5 cm]. I-3f ibonisa idatha yokukhokha ye-EWNS eyisisekelo.
Kusukela kumabalazwe okugxiliswa kwezinombolo ze-EWNS (Izibalo Ezingeziwe S5 kanye ne-S6), kungabonakala ukuthi indawo yesehlakalo [-6.5 kV, 4.0 cm] inenani lezinhlayiya eziphakeme kakhulu kunesigcawu esingu-[-3.8 kV, 0.5 cm]. Kufanele futhi kuqashelwe ukuthi ukugxilwa kwezinombolo ze-EWNS kwagadwa kuze kufike emahoreni angu-4 (Izibalo Ezingeziwe S5 kanye ne-S6), lapho ukuzinza kwesizukulwane se-EWNS kubonise amazinga afanayo okugxilwa kwezinombolo zezinhlayiyana kuzo zombili izimo.
Umfanekiso 3g ubonisa i-spectrum ye-EPR ngemva kokulawula (ingemuva) ukususa kwe-EWNS ethuthukisiwe kokuthi [-6.5 kV, 4.0 cm]. I-spectrum ye-ROS nayo iqhathaniswa nesisekelo se-EWNS ephepheni elishicilelwe ngaphambilini. Inombolo ebaliwe ye-EWNS esabela nge-spin trap ingu-7.5 × 104 EWNS/s, efana ne-Baseline-EWNS8 eshicilelwe ngaphambilini. I-spectra ye-EPR ibonise ngokucacile ukuba khona kwezinhlobo ezimbili ze-ROS, lapho i-O2- yayidla kakhulu, kuyilapho i-OH• yayikhona ngenani elincane. Ukwengeza, ukuqhathanisa okuqondile kokuqina okuphezulu kubonise ukuthi i-EWNS eyenziwe kahle inokuqukethwe kwe-ROS okuphezulu kakhulu uma kuqhathaniswa ne-EWNS eyisisekelo.
Emkhiwaneni. 4 ikhombisa ukusebenza kahle kwe-EWNS ku-EPES. Idatha iphinde ifinyezwe kuThebula I futhi iqhathaniswe nedatha ye-EWNS yasekuqaleni. Kuzo zombili izimo ze-EUNS, ukufakwa bekusondele ku-100% ngisho nakugesi ophansi ongu-3.0 kV. Ngokujwayelekile, i-3.0 kV yanele ukuzuza u-100% we-deposition kungakhathaliseki ukuthi ishaja ishintshile kanjani. Ngaphansi kwezimo ezifanayo, ukusebenza kahle kokufakwa kwe-Baseline-EWNS kwakungama-56% kuphela ngenxa yokushajwa okuphansi (isilinganiso sama-electron ayi-10 nge-EWNS ngayinye).
Umfanekiso 5 kanye neThebula 2 ifingqa izinga lokungasebenzi kwama-microorganisms afakwe ebusweni bukatamatisi ngemva kokuchayeka cishe ku-40,000 #/cm3 EWNS imizuzu engu-45 ngaphansi kwesimo esifanele [-6.5 kV, 4.0 cm]. I-E. coli e-inoculated ne-L. innocua ibonise ukwehla okuphawulekayo kwelogi engu-3.8 ngemva kwemizuzu engu-45 yokuchayeka. Ngaphansi kwezimo ezifanayo, i-S. enterica ibonise ukuncishiswa kwelogi okuphansi kwamalogi angu-2.2, kuyilapho i-S. cerevisiae ne-M. parafortuitum ibonise ukuncishiswa kwelogi engu-1.0.
Ama-Electron micrographs (Umfanekiso 6) abonisa izinguquko ezibonakalayo ezidalwe yi-EWNS ku-E. coli, Salmonella enterica, namaseli e-L. innocua aholela ekungasebenzini. Amabhaktheriya okulawula abonise ulwelwesi lwamaseli olungaguquki, kuyilapho amabhaktheriya eveziwe ayewonakalise ulwelwesi lwangaphandle.
I-electronic imaging microscopic yokulawula kanye namagciwane aveziwe aveze ukulimala kolwelwesi.
Idatha yezakhiwo ze-physicochemical ye-EWNS ethuthukisiwe ngokuhlangene ibonisa ukuthi izici ze-EWNS (inkokhelo engaphezulu nokuqukethwe kwe-ROS) zithuthukiswe kakhulu uma kuqhathaniswa nedatha yesisekelo ye-EWNS eshicilelwe ngaphambili8,9,10,11. Ngakolunye uhlangothi, usayizi wabo wahlala ebangeni le-nanometer, elifana kakhulu nemiphumela eshicilelwe ngaphambilini, evumela ukuba bahlale emoyeni isikhathi eside. I-polydispersity ephawuliwe ingachazwa ngoshintsho ekushajeni okungaphezulu, okunquma ubukhulu bomphumela we-Rayleigh, ukungahleliwe, kanye nokuhlangana okungenzeka kwe-EWNS. Kodwa-ke, njengoba kuchazwe u-Nielsen et al.22, ukushaja okuphezulu kwendawo kunciphisa ukuhwamuka ngokwandisa ngempumelelo amandla angaphezulu/ukushuba kokwehla kwamanzi. Le thiyori iqinisekiswe ngokuhlolwa kwe-microdroplets22 kanye ne-EWNS ekushicilelweni kwethu kwangaphambili8. Ukulahlekelwa isikhathi esengeziwe kungase futhi kuthinte usayizi futhi kube nomthelela ekusabalaliseni kosayizi obukiwe.
Ngaphezu kwalokho, inkokhiso ngesakhiwo ngasinye imayelana ne-22-44 e-, kuye ngezimo, ephakeme kakhulu uma iqhathaniswa ne-EWNS eyisisekelo, enenani elilinganiselwe lama-electron angu-10 ± 2 isakhiwo ngasinye. Nokho, kufanele kuqashelwe ukuthi lena inkokhiso evamile ye-EWNS. Seto et al. Kukhonjisiwe ukuthi inkokhiso ayifani futhi ilandela ukusabalalisa okujwayelekile21. Uma kuqhathaniswa nomsebenzi wethu wangaphambilini, ukuphinda kabili inkokhiso engaphezulu kuphinda kabili ukusebenza kahle kwe-deposition ohlelweni lwe-EPES cishe ku-100%11.